The document, first reported by the New York Times and Gannett News Service and published online Thursday by New York State public radio, references sections of DEC's draft environmental review that deal with health impacts from shale gas drilling and high-volume hydraulic fracturing, or fracking. The report concludes that adverse health impacts will be prevented if DEC's guidelines are followed.

A DEC spokeswoman said the report is an outdated draft.

"The document is not a health assessment, is nearly a year old, and does not reflect final DEC policy," spokeswoman Emily DeSantis said in a statement.

The eight-page document references sections of DEC's 1,500-page environmental impact study of shale gas development. A final version of that study, which is expected to be released in February, will include revisions based on public comment and a health impact review now under way by the state Health Department and three outside experts, DEC has said.

Materials being reviewed by the outside experts haven't been made public and environmental groups have criticized Gov. Andrew Cuomo's administration for conducting the health review in secret. The Cuomo administration has repeatedly delayed the release of health-related documents requested by The Associated Press and Environmental Advocates under the Freedom of Information Law.

"We don't have any idea what the administration is doing," said Katherine Nadeau of Environmental Advocates. "They're just saying to the people of the state, 'Just trust us.' It makes a mockery of good government."

Industry groups said the leaked document confirms that fracking can be done safely, and expressed confidence in the state's health review process.

"We respect the process the governor has established, and trust that in the end the interest of the people will come before fear mongering and politics," said Karen Moreau, executive director of the New York State Petroleum Council.

Cuomo has said he'll lift the state's ban on fracking if it's shown to be safe. The state has had a moratorium in effect since July 2008, when DEC began its review of the impacts of fracking, a technology that frees gas from shale by blasting millions of gallons of water mixed with sand and chemical additives at the underground rock.

The document appears to have been written for inclusion in the larger environmental impact study. It describes potential health risks associated with fracking and shale gas development such as exposure to chemicals, contamination of drinking water sources, air pollution, and contact with radioactive elements brought up from deep underground. It references sections of the environmental impact study that address each potential risk and related safety measures to prevent harm.

The document says "significant adverse impacts on human health are not expected from routine (fracking) operations. When spills or accidents occur, the department has identified numerous additional mitigation measures, including emergency-response planning, setbacks and buffers, so that significant exposures to people and resources on which they rely are unlikely."

One of the biggest criticisms health and environmental groups have concerning DEC's environmental impact study is that it doesn't include a comprehensive health impact study conducted by outside experts with public participation. The DEC document says state and federal laws support DEC's contention that public health and safety should be addressed in an environmental impact study.

DEC Commissioner Joe Martens in September rejected calls for a separate health study by outside experts. Instead, he said the Health Department and a panel of outside experts would review what DEC had already done.

Although its overall environmental impact study hasn't been completed, the agency released related fracking regulations last month with a public comment period that ends on Jan. 11. The agency has until the end of February to adopt those regulations. Missing that deadline would mean reopening the regulatory process with additional public comment.